Table 2. Observational studies.
| First author (yr) | Investigation type | Population | Participants |
|---|---|---|---|
| Byczkowski, Munafo & Britto (2011) | Retrospective observational study | 1,900 | 498 |
| Goel et al. (2011b) | Retrospective data analysis with adopters | 7,088 | 4,891 |
| Nielsen, Halamka & Kinkel (2012) | Retrospective chart review | 240 | 154 |
| Sarkar et al. (2010) | Telephone, web and written survey | 14,102 | 5,671 |
| Sarkar et al. (2011) | Telephone, web and written survey | 14,102 | 5,671 |
| Yamin et al. (2011) | Data analysis comparing adopters and non-adopters | 75,056 | 32,274 |